Understanding Custom Hooks in React JS: A Comprehensive Guide
Introduction
Custom Hooks in React JS is one of the hottest topics in app development. Custom hooks support reusability if I say in one line then Custom hooks are reusable functions. When we have the same React JS component logic that needs to be used multiple times then, in that case, we create custom hooks that extract component logic and put that logic inside it then we can use these custom hooks across components wherever we need a similar kind of component logic to be integrated.
Basics of React Hooks
Introduction to React Hooks
React hooks are reusable functions that use state and other React features in functional components. They were introduced in React 16.8, bringing a new way to handle state and lifecycle methods without writing class components.
Commonly Used Built-in Hooks
Some of the commonly used built-in hooks include:
- useState: For managing state in a functional component.
- useEffect: For handling side effects like data fetching and subscriptions.
- useContext: For accessing context values.
- useReducer: For managing complex state logic.
Why Create Custom Hooks?
Benefits of Using Custom Hooks
Custom hooks allow you to extract component logic into reusable functions. This helps to maintain code reusability and cleaner code by separating logic from UI. Custom hooks are compatible with functional components.
Scenarios Where Custom Hooks are Useful
Custom hooks help the developer to deal with repeated logic across components, such as data fetching, form handling, authentication, and more.
Getting Started with Custom Hooks
Prerequisites
Before diving into custom hooks, you should be familiar with basic React concepts and built-in hooks like useState and useEffect.
Basic Structure of a Custom Hooks in React JS
A custom hook is a JavaScript function whose name starts with “use” and can call other hooks. Here’s a simple example:
function useCustomHook() { // Logic here }Creating Your First Custom Hook
Step-by-Step Guide
- Define the Hook Function: Start with a function that performs a specific task.
- Use Built-in Hooks: Inside your function, use built-in hooks to manage state and side effects.
- Return Necessary Values: Return any values or functions that the consuming component will need.
Example: Creating a Custom Hook for Fetching Data and Integrate it
import { useState, useEffect } from 'react';
function useFetch(url) {
const [data, setData] = useState(null);
const [loading, setLoading] = useState(true);
const [error, setError] = useState(null);
useEffect(() => {
fetch(url)
.then(response => response.json())
.then(data => {
setData(data);
setLoading(false);
}).catch(error => {
setError(error);
setLoading(false);
});
}, [url]);
return { data, loading, error };
}
// Component
const TekodyComponent = () => {
const { data, loading, error } = useFetch('URL');
if(loading) {
return "Loading...";
}
return <Component data={data} />
}Understanding the Hook Rules
The Golden Rules of Hooks
- Call Hooks at the Top Level: Avoid calling hooks inside loops, conditions, or nested functions.
- Call Hooks from React Functions: Only call hooks from functional components or other custom hooks.
Why should we not call/use custom hooks inside loops, conditions, or nested functions?
React JS relies on order. We should ensure that Hooks are being called in the same order each time. This is how this order allows React to correctly preserve the state of Hooks between multiple useState and useEffect calls.
if we call hooks inside conditions, loops, and nested functions then there is a possibility that Hooks’ execution order can be disturbed which can lead to wrong state calculation.
How to Follow These Rules in Custom Hooks
Ensure that your custom hooks adhere to these rules to avoid common pitfalls and ensure predictable behavior.
Best Practices for Custom Hooks in React JS
Naming Conventions
Always prefix your custom hook with “use” to follow the convention and let React know it’s a hook.
Code Organization
Organize your hooks in a dedicated directory, such as src/hooks, to keep your project structure clean.
Documentation
Document your custom hooks well, explaining what they do, their parameters, and what they return.
Advanced Custom Hook Patterns
Using Custom Hooks in React JS for Form Handling
You can create custom hooks to manage form states and validations. For example, useForm could handle form inputs and errors.
Custom Hooks in React JS for State Management
Custom hooks can manage complex state logic, providing a more intuitive and reusable way to handle state compared to traditional methods.
Optimizing Custom Hooks in React JS
Performance Considerations
Be mindful of performance by using techniques like memoization to avoid unnecessary re-renders.
Memoization with Custom Hooks
Use useMemo and useCallback within your custom hooks to memoize expensive calculations and functions.
Testing Custom Hooks in React JS
Importance of Testing
Testing custom hooks ensures they work as expected and helps catch bugs early.
Tools and Techniques for Testing Hooks
Use tools like react-hooks-testing-library to test your custom hooks in isolation, ensuring they behave correctly under different scenarios.
Debugging Custom Hooks in React JS
Common Issues and Fixes
Issues like infinite loops in useEffect or state not updating correctly can arise. Ensure you handle dependencies and state updates properly.
Debugging Tools and Tips
Use tools like React DevTools and console logging to debug and trace issues within your custom hooks.
Real-world Examples of Custom Hooks in React JS:
Custom Hook for Authentication
A custom hook like useAuth can manage user authentication states and actions, providing a reusable solution across your application.
Custom Hook for Theming
useTheme can help manage theme states, allowing components to easily toggle between light and dark modes.
Integrating Custom Hooks in React JS Project
Best Practices for Integration
Gradually integrate custom hooks into your project by refactoring existing logic into hooks, ensuring a smooth transition.
Refactoring Existing Code to Use Custom Hooks
Identify repeated logic in your components and refactor them into custom hooks for cleaner and more maintainable code.
Community Resources and Further Learning
Popular Custom Hooks Libraries
Explore libraries like usehooks.com and react-use that offer a variety of pre-built custom hooks to speed up your development.
Learning Resources and Tutorials
Engage with tutorials, courses, and community forums to continuously learn and improve your custom hooks skills.
Conclusion
I am wrapping up this article (Custom Hooks in React JS). Hopefully, this will be helpful while you are planning to write a custom hook in your application to deal with repeated component logic. we:
- Explained why we need custom hooks
- Explained how we should write the custom hooks
- Explained the golden rules of hooks
- Explained why we should not use custom hooks inside the condition or in the loop
FAQs
What are Custom Hooks in React?
Custom hooks are JavaScript functions that allow you to reuse stateful logic across different components.
Can Custom Hooks replace all built-in Hooks?
No, custom hooks are meant to complement built-in hooks by encapsulating and reusing logic, not to replace them.
How do I share the state between components using Custom Hooks?
By using custom hooks, you can share logic and state management across components, making your code more reusable.
Are there any limitations to using Custom Hooks?
Custom hooks follow the same rules as regular hooks and can be subject to issues like improper handling of dependencies in useEffect.
What are some common pitfalls to avoid when creating Custom Hooks?
Avoid calling hooks inside loops or conditions, and ensure your custom hooks are well-documented and tested.
Some useful links:
Built-in React Hooks – https://react.dev/reference/react/hooks
React Js job support – https://tekody.com/services/react-js-job-support/
Angular Js Job Support – https://tekody.com/services/angular-js-job-support/
